I cannot get the boolean difference modifier to work for these 2 cylinders as shown. What am I doing wrong? The normals on both cylinders are point outwards
What you are doing works just fine. You can't see that it works because the Boolean modifier is non-destructive. Cylinder.001 still exists.
You can do one of several things, including but not limited to:
- Hide Cylinder.001 by clicking the eye icon in the outliner, or selecting it and typing H in the 3d Viewport resulting in the eye looking closed;
- Placing it in a different collection and hiding that collection;
- Applying the modifier and deleting Cylinder.001; or
- Changing its Viewport Display property to Bounds or Wire so that you can see that it still exists, but also see the Boolean effect.
Your choice depends on your workflow. A very popular workflow is to
- Create a separate collection called something like Cutters and move it to that collection
- Change its Viewport Display to wire or bounds.
This gives you the flexibility of hiding all of the cutters you are using, or only a few of them, while still allowing you to see both the result of the Boolean and why that result occurred. Here's an example:
The 3D Viewport: